From 4eefdfc5b7d0b86a523683de2a90da910b77a106 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <bitcoin-dev@wuille.net>
Date: Sat, 21 Feb 2026 10:27:59 -0500
Subject: [PATCH] clusterlin: rescale costs (preparation)

---
 src/cluster_linearize.h             |  4 ++--
 src/test/fuzz/cluster_linearize.cpp |  4 ++--
 src/test/util/cluster_linearize.h   | 16 ++++++++--------
 src/txmempool.h                     |  2 +-
 4 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/src/cluster_linearize.h b/src/cluster_linearize.h
index 57df4512697..ea0d6bd8346 100644
--- a/src/cluster_linearize.h
+++ b/src/cluster_linearize.h
@@ -486,9 +486,9 @@ public:
     inline void StartOptimizingBegin() noexcept {}
     inline void StartOptimizingEnd(int num_chunks) noexcept {}
     inline void ActivateBegin() noexcept {}
-    inline void ActivateEnd(int num_deps) noexcept { m_cost += num_deps + 1; }
+    inline void ActivateEnd(int num_deps) noexcept { m_cost += 38 * num_deps + 38; }
     inline void DeactivateBegin() noexcept {}
-    inline void DeactivateEnd(int num_deps) noexcept { m_cost += num_deps + 1; }
+    inline void DeactivateEnd(int num_deps) noexcept { m_cost += 38 * num_deps + 38; }
     inline void MergeChunksBegin() noexcept {}
     inline void MergeChunksMid(int num_txns) noexcept {}
     inline void MergeChunksEnd(int num_steps) noexcept {}
diff --git a/src/test/fuzz/cluster_linearize.cpp b/src/test/fuzz/cluster_linearize.cpp
index adee8f2ed90..9b07bf00eb2 100644
--- a/src/test/fuzz/cluster_linearize.cpp
+++ b/src/test/fuzz/cluster_linearize.cpp
@@ -1043,7 +1043,7 @@ FUZZ_TARGET(clusterlin_linearize)
     }
 
     // Invoke Linearize().
-    max_cost &= 0x7ffff;
+    max_cost &= 0x3fffff;
     auto [linearization, optimal, cost] = Linearize(
         /*depgraph=*/depgraph,
         /*max_cost=*/max_cost,
@@ -1242,7 +1242,7 @@ FUZZ_TARGET(clusterlin_postlinearize_tree)
 
     // Try to find an even better linearization directly. This must not change the diagram for the
     // same reason.
-    auto [opt_linearization, _optimal, _cost] = Linearize(depgraph_tree, 100000, rng_seed, IndexTxOrder{}, post_linearization);
+    auto [opt_linearization, _optimal, _cost] = Linearize(depgraph_tree, 1000000, rng_seed, IndexTxOrder{}, post_linearization);
     auto opt_chunking = ChunkLinearization(depgraph_tree, opt_linearization);
     auto cmp_opt = CompareChunks(opt_chunking, post_chunking);
     assert(cmp_opt == 0);
diff --git a/src/test/util/cluster_linearize.h b/src/test/util/cluster_linearize.h
index f50a51bd1a5..f8ffb5ea4e5 100644
--- a/src/test/util/cluster_linearize.h
+++ b/src/test/util/cluster_linearize.h
@@ -402,14 +402,14 @@ inline uint64_t MaxOptimalLinearizationCost(DepGraphIndex cluster_count)
     // *some* reasonable cost bound, optimal linearizations are always found.
     static constexpr uint64_t COSTS[65] = {
         0,
-        0, 4, 10, 34, 76, 156, 229, 380,
-        441, 517, 678, 933, 1037, 1366, 1464, 1711,
-        2111, 2542, 3068, 3116, 4029, 3467, 5324, 5402,
-        6481, 7161, 7441, 8183, 8843, 9353, 11104, 11455,
-        11791, 12570, 13480, 14259, 14525, 12426, 14477, 20201,
-        18737, 16581, 23622, 28486, 30652, 33021, 32942, 32745,
-        34046, 26227, 34662, 38019, 40814, 31113, 41448, 33968,
-        35024, 59207, 42872, 41277, 42365, 51833, 63410, 67035
+        0, 176, 440, 1496, 3344, 6864, 10076, 16720,
+        19404, 22748, 29832, 41052, 45628, 60104, 64416, 75284,
+        92884, 111848, 134992, 137104, 177276, 152548, 234256, 237688,
+        285164, 315084, 327404, 360052, 389092, 411532, 488576, 504020,
+        518804, 553080, 593120, 627396, 639100, 546744, 636988, 888844,
+        824428, 729564, 1039368, 1253384, 1348688, 1452924, 1449448, 1440780,
+        1498024, 1153988, 1525128, 1672836, 1795816, 1368972, 1823712, 1494592,
+        1541056, 2605108, 1886368, 1816188, 1864060, 2280652, 2790040, 2949540
     };
     assert(cluster_count < std::size(COSTS));
     // Multiply the table number by two, to account for the fact that they are not absolutes.
diff --git a/src/txmempool.h b/src/txmempool.h
index 5a870f4cc32..d7b7de6e3b7 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -51,7 +51,7 @@ static const uint32_t MEMPOOL_HEIGHT = 0x7FFFFFFF;
 
 /** How much linearization cost required for TxGraph clusters to have
  * "acceptable" quality, if they cannot be optimally linearized with less cost. */
-static constexpr uint64_t ACCEPTABLE_COST = 1'700;
+static constexpr uint64_t ACCEPTABLE_COST = 75'000;
 
 /** How much work we ask TxGraph to do after a mempool change occurs (either
  * due to a changeset being applied, a new block being found, or a reorg). */